Am J Bot. 1998 May;85(5):629.
Mitochondrial (mt) DNA variation in Japanese beech, Fagus crenata (Fagaceae), was studied in 17 populations distributed throughout the species' range. Total genomic DNA of samples from single trees representing each of 12 populations were digested with 18 restriction enzymes and hybridized with three probes containing coxI, coxIII, and atpA gene sequences. Thirty-four of the 54 enzyme/probe combinations showed polymorphisms and all the individuals were subsequently analyzed with six combinations of three probes and two enzymes. Restriction fragment length polymorphisms were evident around all three genes, allowing the identification of eight distinct haplotypes. Haplotype diversity within the populations was found to be very low (HS = 0.031), but population differentiation to be much higher (GST = 0.963). The mtDNA variation was strikingly different from allozyme variation (HS = 0.209; GST = 0.039). Gene flow for maternally inherited mtDNA should be restricted to seed dispersal while nuclear gene flow occurs by both seed and pollen dispersal. Therefore, the difference in the variation between mtDNA and allozymes may be largely a result of the much higher rate of gene flow associated with pollen dispersal than with seed dispersal. The mtDNA variation displayed strong geographic structure, which may reflect the species' distribution in the last glacial maximum and subsequent colonization, and probably also reflects intraspecific phylogeography of the species.
对分布于日本山毛榉（壳斗科）整个分布区内的 17 个种群的线粒体（mt）DNA 变异进行了研究。从代表 12 个种群中的每一个种群的单株采集的总基因组 DNA 用 18 种限制酶消化，并与包含 coxI、coxIII 和 atpA 基因序列的三个探针杂交。在 54 种酶/探针组合中，有 34 种显示出多态性，所有个体随后用三种探针和两种酶的六种组合进行分析。在所有三个基因周围都存在限制性片段长度多态性，从而能够鉴定出 8 种不同的单倍型。发现种群内的单倍型多样性非常低（HS = 0.031），但种群分化要高得多（GST = 0.963）。mtDNA 变异与等位酶变异明显不同（HS = 0.209；GST = 0.039）。母系遗传的 mtDNA 的基因流应该仅限于种子散布，而核基因流则通过种子和花粉散布发生。因此，mtDNA 与等位酶之间变异的差异可能主要是由于花粉散布与种子散布相比具有更高的基因流速率所致。mtDNA 变异显示出强烈的地理结构，这可能反映了物种在末次冰期最大值和随后的殖民化过程中的分布，也可能反映了该物种的种内系统地理学。
